Show the featured image in the portfolio itself

Hi there,

I have read man posts on this forum about people wanting to get rid of the featured image in the portfolio item itself.
To me it is just the other way, once I have set up the featured image on a portfolio item, I would like to have the same image in the portfolio itself, like sort of an header, wich automatically scales to the size of the post.

Sorry for my bad explaining but I guess you understand what I mean.

Thanks in advance.